ABSTRACT
Nano uids belong to a new class of heat transfer uids, which are engineered by dispersing nanometer-sized (typically less than 100 nm) solid particles, rods, or tubes in conventional heat transfer uids such as water, ethylene glycol (EG), and engine oil (EO). In recent years, nano uids have evoked immense interest from researchers of various disciplines because of their superior thermal properties and potential applications in diverse elds such as microelectronics, micro uidics, transportation, and biomedical. Nano uids are found to possess higher thermal properties such as e ective thermal conductivity and thermal di usivity compared to their base uids, and the magnitudes of these properties increase remarkably with increasing nanoparticle volume fraction. Particle size and shape as well as uid temperature also have in uence on the enhancement of the e ective thermal conductivity of nano uids. However, there are inconsistencies in reported experimental results and controversies in the proposed mechanisms for the enhanced thermal conductivity of nano uids. e aim of this chapter is to present and discuss the thermophysical properties that include thermal conductivity, thermal di usivity, speci c heat, and viscosity of nano uids under the in uences of various factors such as concentration, size and shape of nanoparticles, and uid temperature. e potential applications, synthesis, thermal conductivity mechanisms, and measurement techniques of nano uids, together with a brief review of representative results from the literature on these properties, are also presented.
